Device for exchanging electron sources in electrical discharge devices



g- 3, 1966 YOSHIHISA MINAMIKAWA ETAL 3,

DEVICE FOR EXCHANGING ELECTRON SOURCES IN ELECTRICAL DISCHARGE DEVICES Filed June 10, 1965 H T70 2/05 V 3 ,268,759 Ce Patented August 23, 1956 3,268,759 DEVICE FOR EXCHANGING ELECTRON SOURCES IN ELECTRICAL DISCHARGE DEVICES Yoshihisa Minamikawa and Shirljiro Katagiri, Kodalrashi, Tokyo, Japan, assignors to Hitachi, Ltd., Tokyo, Japan, 'a corporation of Japan Filed June 10, 1963, Ser. No. 286,804 Claims priority, application Japan, June 14, 1962, 37/2 4,283 Claims. (Cl. 313237) This invention relates to a device for exchanging articles in high-pressure vessels. More particularly, this invention relates to a device for exchanging electrical articles, such as an electron source, as are used in conjunction with high voltage charged particle accelerators and the like.

In an apparatus such as a high voltage charged particle accelerator of conventional construction, it is a usual practice to enclose associated equipment such as a high voltage supply and an accelerating tube section within a high-pressure vessel of metallic material for the purpose of minimizing any danger to humans and to reduce the space requirement for installation. Then said vessel is filled with an insulating gas at a high pressure for enclosure therein to provide a high degree of insulation. When a heated filament, for example, is used as an electron source or an electron gun, there may arise a necessity of exchanging the same for a new one in the event of the breakdown of such a filament. According to a conventional manner of replacing such a filament, said metallic vessel is detached from the associated apparatus to expose and exchange the electron source which is disposed on the top of the accelerator. This exchanging operation of the electron source however involves troublesome manipulations such as dismounting and remounting of said vessel as well as increased costs due to loss of the insulating gas.

With these drawbacks and other difliculties encountered in the prior art apparatus of this kind in view, it is the primary object of this invention to provide a device for exchanging in an extremely easy manner an article such as an electron source enclosed in a structure at a high pressure and high voltage.

The device of the present invention for exchanging an article placed in a high-pressure vessel comprises a tubular member mounted on a part of the wall of the said high-pressure vessel to be inserted into the said vessel from the outside, while maintaining a gas-tight condition, an end face of which contacts with an upper face of a supporting member for said article in the said high-pressure vessel in a manner to shield the said article in a gas-tight condition when exchanging the said article, and a passage formed through the said tubular member through which the said article is exchanged.

There are further objects and particularities of this in vention which Will become obvious in the following description with reference to the accompanying drawing in which:

The sole figure diagrammatically illustrates a sectional view through the principal parts of a high voltage charged particle accelerator to which the device according to this invention is adapted.

Although the sole figure and the description thereof are directed to a specific embodiment wherein the device of this invention is adapted to a high voltage charged particle accelerator, it is by no means intended to limit the invention to this specific embodiment.

Referring now to the drawing, a high voltage charged particle accelerator comprises an accelerating tube section 1 on the top of which an electron source 2 or an electron gun is mounted by means of a supporting member 3 such as an annular plate for supporting thereon said said electron source 2. The accelerating tube section 1 is surrounded by a high voltage supply 4 in the conventional manner.

All these accelerator elements are contained in a vessel 5 of metallic material which is maintained at a high pressure with a gas of insulating nature such as sulfur hexafluoride, Freon or the like enclosed therein. In order to assure a gas-tight relationship between the high pressure portions of the apparatus filled with the insulating gas and the accelerating tube section 1, which is maintained in a high vacuum condition, a gasket 6 of rubber or like material is provided about the upper peripheral portion of the electron source 2 where the electron source 2 is fitted to the supporting member 3.

The inventive device of this invention comprises. a generally cylindrical member 7 which is disposed on the top of said vessel 5 on the side opposite the electron source 2 in a manner to replace the otherwise continuous wall of the vessel 5 and movable toward and away from the electron source 2 for dismounting and remounting said electron source 2 as required. The cylindrical member 7 has an internal diameter of such a dimension that said electron source 2 can be adequately accommodated therewithin. When urged inwardly through the vessel 5 toward the article exchanging position, the cylindrical member 7 finally abuts the supporting member 3 disposed on the top of the accelerating tube section 1 in a manner that the lower annular face 15 thereof encircles the electron source 2, the inwardly urged position of said cylindrical member 7 being shown in dotted lines at 7. The gas-tight operation of the cylindrical member 7 throughout its operating position and its positions when not in operation are maintained by gaskets 8 and 9 of rubber or like material, the gasket 8 keeping a gas-tight relationship at the abutting face between the lower face 15 of said cylindrical member 7 and the supporting member 3 at the lowered position of said cylindrical member 7, and the gasket 9 keeping a gas-tight relationship at the abutting portion between the vessel wall and the outer peripheral surface of the cylindrical member '7 at any position of said cylindrical member 7. The cylindrical member 7 may be provided thereinside with a piston 10 which is slidable in the axial direction of the cylindrical member 7. Axial recesses 11 are 'bored in the bottom portion of the piston 10 and have such a configuration that they will snugly fit over the projections or pins 13 of complementary configuration provided on the electron source 2 so that the electron source 2 can be carried with the piston 10 for the exchanging operation. A gasket 12 of rubber or like material is disposed at the abutting face between the peripheral surface of said piston 10 and the inner Wall of the cylindrical member 7 to assure the gas-tight relationship therebetween at all times. A corona shield 14 for high voltage is illustrated as mounted to surround the electron source 2 of the apparatus in the usual manner.

In utilizing the device of this invention having the above arrangement in a dismounting operation, at first the cylindrical member 7 is actuated by a suitable external means (not shown) to be lowered from the normal starting position shown in solid lines and finally secured at the position 7 (dotted lines), where the lower face 15 of the cylindrical member 7 abuts the rubber gasket 8 disposed on the supporting member 3 for the electron source 2. Thereby, the interior of the cylindrical member 7 is isolated from the surrounding gas chamber and any flow of gas thereinto can be positively shut 01f. Under this condition, application of high voltage is stopped and the interior of the accelerating tube section 1 is made to take atmospheric pressure. Then, the piston 10 is lowered by a suitable means (not shown) until the recesses 11 fit on the pins 13 of the electron source 2 for carrying the used or otherwise damaged electron source 2 with the piston 10. After the electron source 2 has been carried on the piston 10, the piston can be pulled upwardly to take out the electron source 2. It will be understood that the remounting operation of a new electron source 2 can likewise be easily performed, in which operation the new electron source is fitted on the bottom of the piston 10, said piston being lowered down to the predetermined position on the supporting member 3 at the top of the accelerating tube section 1 and said new electron source being mounted in place. When a large gas pressure is employed in the vessel, such power means as electric power, compressed air pressure, or gravity may be utilized in the exchanging device since a relatively large force may be required to lower the cylindrical member 7.

From the foregoing description, it will be readily seen that the device according to the invention has remarkable practical elfects in that an article such as an electron source can be exchanged in an extremely short time with a minimum loss of gas during such an operation since the article placed inside the vessel can be taken out while the gas is kept enclosed in the vessel under the same condition as in the normal operating condition. Although this invention has been described with reference to the preferred single embodiment of the exchange of an electron source, it should be understood that the article to be exchanged is in no way limited to such a specific one and the device of this invention is similarly elfective for any cases wherein it is desired to take out any article disposed in a high-pressure chamber. It will also be understood that the cylindrical member 7 which forms an article exchanging passage is not necessarily of a circular cross section and may be any tubular member having a predetermined length.

By the device of the present invention, not only one article but also more than one article can be exchanged.

We claim:

1. A device for exchanging an article in a high-pressure vessel which comprises a tubular member, said tubular member being adapted to slide through an opening in the wall of said high-pressure vessel so that at the innermost position of said tubular member the end face thereof engages a fixed supporting member within said vessel upon which said article to be exchanged is mounted, said tubular member being in a gas-tight, sealed relationship within said high-pressure vessel, and piston means within said tubular member for effecting the exchange of said article.

2. A device for exchanging an article in a high-pressure vessel which comprises a tubular member, said tubular member being adapted to slide through an opening in the wall of said high-pressure vessel so that at the innermost position of said tubular member the end face thereof engages a fixed supporting member within said vessel upon which said article to be exchanged is mounted, said tubular member being in a gas-tight, sealed relationship within said high-pressure vessel, and piston means within said tubular member for effecting the exchange of said article, said piston means having recesses at the inner end portion thereof for engaging said article when the piston is moved to its innermost position.

3. The device of claim 1, wherein said article is an electrical article.

4. A device for exchanging an electron source in a high-pressure vessel enclosing a high voltage charged particle accelerator including a high voltage supply and an accelerating tube and being filled with an insulating gas at high pressure which comprises a tubular member, said tubular member being adaped to slide through an opening in the wall of said high-pressure vessel so that at the innermost position of said tubular member the end face thereof engages a fixed supporting member within said vessel upon which said electron source to be exchanged is mounted, said tubular member being in a gas-tight, sealed relationship within said high-pressure vessel, and piston means within said tubular member for effecting the exchange of said electron source.

5. A device for exchanging an electron source in a high-pressure vessel enclosing a high voltage charged particle accelerator including a high voltage supply and an accelerating tube and being filled with an insulating gas at high pressure which comprises a tubular member, said tubular member being adapted to slide through an opening in the wall of said high-pressure vessel so that at the innermost position of said tubular member the end face thereof engages a fixed supporting member within said vessel upon which said electron source to be exchanged is mounted, said tubular member being in a gas-tight, sealed relationship with said high-pressure vessel, and piston means within said tubular member for effecting the exchange of said electron source, said piston means having recesses at the inner end portion thereof for engaging said electron source when the piston is moved to its innermost position.

References Cited by the Examiner UNITED STATES PATENTS 714,989 12/1902 Worthington 29-213 X 965,054 7/1910 Weekes 29-213 1,690,056 10/1928 Coleman 313-237 1,736,561 11/1929 Wattel 29-213 X 2,218,886 10/1940 Krause 313-237 2,301,955 11/ 1942 Krause 313-237 JOHN W. HUCKERT, Primary Examiner.

MYRON C. KRUSE, Examiner.

A. J. JAMES, Assistant Examiner. 

1. A DEVICE FOR EXCHANGING AN ARTICLE IN A HIGH-PRESSURE VESSEL WHICH COMPRISES A TUBULAR MEMBER, SAID TUBULAR MEMBER BEING ADAPTED TO SLIDE THROUGH AN OPENING IN THE WALL OF SAID HIGH-PRESSURE VESSEL SO THAT AT THE INNERMOST POSITION OF SAID TUBULAR MEMBER THE END FACE THEREOF ENGAGES A FIXED SUPPORTING MEMBER WITHIN SAID VESSEL UPON WHICH SAID ARTICLE TO BE EXCHANGED IS MOUNTED, SAID TUBULAR MEMBER BEING IN A GAS-TIGHT, SEALED RELATIONSHIP WITHIN SAID HIGH-PRESSURE VESSEL, AND PISTON MEANS WITHIN SAID TUBULAR MEMBER FOR EFFECTING THE EXCHANGE OF SAID ARTICLE. 